The invention generally relates to supports for rocket engines, and more particularly to an improved system for pivotally displacing an engine-mounting platform, whereby a relocation of the engine's thrust vector relative to the vehicle's center of gravity is achieved.
It is, of course, recognized that maximum thrust is achievable for a multi-engine system when the thrust vectors are arranged in parallelism. However, for reasons fully appreciated by those familiar with the design and operation of rocket-propelled vehicles, it is considered to be impossible to mount multiple engines in a manner such that the thrust vector of more than one engine will pass through the center of gravity of the vehicle and yet be oriented in parallelism with the vehicle's line of flight. This design restriction has lead to numerous problems encountered during in-flight operations. For example, it is not uncommon to experience an abort resulting from failure of one engine during stage thrust operation.
In order to avoid loss of directional control, such as tumbling and the like, as a consequence of engine malfunction in a multi-engine system, it is common practice to shut down the engine opposite the failing engine, or to increase the thrust of the remaining engines on the same side of the vehicle. Either of these alternatives are undesirable for obvious reasons. While it is possible to partially overcome this problem by pre-positioning thrust vectors to pass through the center of gravity, it has been found for vehicles having engine thrust vectors pre-positioned through some nominal center of gravity, two problems generally are encountered. The first being that the resultant thrust is never as great as it is for vehicles having engine thrust vectors pre-positioned in parallelism, and secondly, the center of gravity tends to shift continuously throughout stage operation, because of propellant depletion and similarly initiated changes in mass. Consequently, even where the thrust vectors are extended through a nominal center of gravity, it is apparent that only at one point in stage operation are the pre-positioned thrust vectors in fact extended through the center of gravity.
It has been suggested that engine gimbal actuators larger than are required for nominal operational control be provided for achieving thrust vector relocation. However, the mass and complexity of such gimbal actuator systems tend to render their use impractical.
Because of the existence of these various problems and alternative trade-offs, designers of rocket-propelled vehicles continuously are faced with the decision of whether to orient thrust vectors in parallelism or to arrange the engines so that the thrust vectors are extended through the center of gravity of the vehicle.
It is therefore the general purpose of the instant invention to provide an improved system for a rocket-propelled vehicle through which a selective relocation of the thrust vectors for rocket engines is facilitated whereby maximum thrust may be achieved and directional stability afforded the vehicle.